| /**************************************************************************** |
| ** |
| ** Copyright (C) 2016 The Qt Company Ltd. |
| ** Copyright (C) 2015 Alex Trotsenko <alex1973tr@gmail.com> |
| ** Contact: https://www.qt.io/licensing/ |
| ** |
| ** This file is part of the QtCore module of the Qt Toolkit. |
| ** |
| ** $QT_BEGIN_LICENSE:LGPL$ |
| ** Commercial License Usage |
| ** Licensees holding valid commercial Qt licenses may use this file in |
| ** accordance with the commercial license agreement provided with the |
| ** Software or, alternatively, in accordance with the terms contained in |
| ** a written agreement between you and The Qt Company. For licensing terms |
| ** and conditions see https://www.qt.io/terms-conditions. For further |
| ** information use the contact form at https://www.qt.io/contact-us. |
| ** |
| ** GNU Lesser General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU Lesser |
| ** General Public License version 3 as published by the Free Software |
| ** Foundation and appearing in the file LICENSE.LGPL3 included in the |
| ** packaging of this file. Please review the following information to |
| ** ensure the GNU Lesser General Public License version 3 requirements |
| ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. |
| ** |
| ** GNU General Public License Usage |
| ** Alternatively, this file may be used under the terms of the GNU |
| ** General Public License version 2.0 or (at your option) the GNU General |
| ** Public license version 3 or any later version approved by the KDE Free |
| ** Qt Foundation. The licenses are as published by the Free Software |
| ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 |
| ** included in the packaging of this file. Please review the following |
| ** information to ensure the GNU General Public License requirements will |
| ** be met: https://www.gnu.org/licenses/gpl-2.0.html and |
| ** https://www.gnu.org/licenses/gpl-3.0.html. |
| ** |
| ** $QT_END_LICENSE$ |
| ** |
| ****************************************************************************/ |
| |
| #include "private/qringbuffer_p.h" |
| #include "private/qbytearray_p.h" |
| #include <string.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| void QRingChunk::allocate(int alloc) |
| { |
| Q_ASSERT(alloc > 0 && size() == 0); |
| |
| if (chunk.size() < alloc || isShared()) |
| chunk = QByteArray(alloc, Qt::Uninitialized); |
| } |
| |
| void QRingChunk::detach() |
| { |
| Q_ASSERT(isShared()); |
| |
| const int chunkSize = size(); |
| QByteArray x(chunkSize, Qt::Uninitialized); |
| ::memcpy(x.data(), chunk.constData() + headOffset, chunkSize); |
| chunk = std::move(x); |
| headOffset = 0; |
| tailOffset = chunkSize; |
| } |
| |
| QByteArray QRingChunk::toByteArray() |
| { |
| if (headOffset != 0 || tailOffset != chunk.size()) { |
| if (isShared()) |
| return chunk.mid(headOffset, size()); |
| |
| if (headOffset != 0) { |
| char *ptr = chunk.data(); |
| ::memmove(ptr, ptr + headOffset, size()); |
| tailOffset -= headOffset; |
| headOffset = 0; |
| } |
| |
| chunk.reserve(0); // avoid that resizing needlessly reallocates |
| chunk.resize(tailOffset); |
| } |
| |
| return chunk; |
| } |
| |
| /*! |
| \internal |
| |
| Access the bytes at a specified position the out-variable length will |
| contain the amount of bytes readable from there, e.g. the amount still |
| the same QByteArray |
| */ |
| const char *QRingBuffer::readPointerAtPosition(qint64 pos, qint64 &length) const |
| { |
| Q_ASSERT(pos >= 0); |
| |
| for (const QRingChunk &chunk : buffers) { |
| length = chunk.size(); |
| if (length > pos) { |
| length -= pos; |
| return chunk.data() + pos; |
| } |
| pos -= length; |
| } |
| |
| length = 0; |
| return nullptr; |
| } |
| |
| void QRingBuffer::free(qint64 bytes) |
| { |
| Q_ASSERT(bytes <= bufferSize); |
| |
| while (bytes > 0) { |
| const qint64 chunkSize = buffers.constFirst().size(); |
| |
| if (buffers.size() == 1 || chunkSize > bytes) { |
| QRingChunk &chunk = buffers.first(); |
| // keep a single block around if it does not exceed |
| // the basic block size, to avoid repeated allocations |
| // between uses of the buffer |
| if (bufferSize == bytes) { |
| if (chunk.capacity() <= basicBlockSize && !chunk.isShared()) { |
| chunk.reset(); |
| bufferSize = 0; |
| } else { |
| clear(); // try to minify/squeeze us |
| } |
| } else { |
| Q_ASSERT(bytes < MaxByteArraySize); |
| chunk.advance(bytes); |
| bufferSize -= bytes; |
| } |
| return; |
| } |
| |
| bufferSize -= chunkSize; |
| bytes -= chunkSize; |
| buffers.removeFirst(); |
| } |
| } |
| |
| char *QRingBuffer::reserve(qint64 bytes) |
| { |
| Q_ASSERT(bytes > 0 && bytes < MaxByteArraySize); |
| |
| const int chunkSize = qMax(basicBlockSize, int(bytes)); |
| int tail = 0; |
| if (bufferSize == 0) { |
| if (buffers.isEmpty()) |
| buffers.append(QRingChunk(chunkSize)); |
| else |
| buffers.first().allocate(chunkSize); |
| } else { |
| const QRingChunk &chunk = buffers.constLast(); |
| // if need a new buffer |
| if (basicBlockSize == 0 || chunk.isShared() || bytes > chunk.available()) |
| buffers.append(QRingChunk(chunkSize)); |
| else |
| tail = chunk.size(); |
| } |
| |
| buffers.last().grow(bytes); |
| bufferSize += bytes; |
| return buffers.last().data() + tail; |
| } |
| |
| /*! |
| \internal |
| |
| Allocate data at buffer head |
| */ |
| char *QRingBuffer::reserveFront(qint64 bytes) |
| { |
| Q_ASSERT(bytes > 0 && bytes < MaxByteArraySize); |
| |
| const int chunkSize = qMax(basicBlockSize, int(bytes)); |
| if (bufferSize == 0) { |
| if (buffers.isEmpty()) |
| buffers.prepend(QRingChunk(chunkSize)); |
| else |
| buffers.first().allocate(chunkSize); |
| buffers.first().grow(chunkSize); |
| buffers.first().advance(chunkSize - bytes); |
| } else { |
| const QRingChunk &chunk = buffers.constFirst(); |
| // if need a new buffer |
| if (basicBlockSize == 0 || chunk.isShared() || bytes > chunk.head()) { |
| buffers.prepend(QRingChunk(chunkSize)); |
| buffers.first().grow(chunkSize); |
| buffers.first().advance(chunkSize - bytes); |
| } else { |
| buffers.first().advance(-bytes); |
| } |
| } |
| |
| bufferSize += bytes; |
| return buffers.first().data(); |
| } |
| |
| void QRingBuffer::chop(qint64 bytes) |
| { |
| Q_ASSERT(bytes <= bufferSize); |
| |
| while (bytes > 0) { |
| const qint64 chunkSize = buffers.constLast().size(); |
| |
| if (buffers.size() == 1 || chunkSize > bytes) { |
| QRingChunk &chunk = buffers.last(); |
| // keep a single block around if it does not exceed |
| // the basic block size, to avoid repeated allocations |
| // between uses of the buffer |
| if (bufferSize == bytes) { |
| if (chunk.capacity() <= basicBlockSize && !chunk.isShared()) { |
| chunk.reset(); |
| bufferSize = 0; |
| } else { |
| clear(); // try to minify/squeeze us |
| } |
| } else { |
| Q_ASSERT(bytes < MaxByteArraySize); |
| chunk.grow(-bytes); |
| bufferSize -= bytes; |
| } |
| return; |
| } |
| |
| bufferSize -= chunkSize; |
| bytes -= chunkSize; |
| buffers.removeLast(); |
| } |
| } |
| |
| void QRingBuffer::clear() |
| { |
| if (buffers.isEmpty()) |
| return; |
| |
| buffers.erase(buffers.begin() + 1, buffers.end()); |
| buffers.first().clear(); |
| bufferSize = 0; |
| } |
| |
| qint64 QRingBuffer::indexOf(char c, qint64 maxLength, qint64 pos) const |
| { |
| Q_ASSERT(maxLength >= 0 && pos >= 0); |
| |
| if (maxLength == 0) |
| return -1; |
| |
| qint64 index = -pos; |
| for (const QRingChunk &chunk : buffers) { |
| const qint64 nextBlockIndex = qMin(index + chunk.size(), maxLength); |
| |
| if (nextBlockIndex > 0) { |
| const char *ptr = chunk.data(); |
| if (index < 0) { |
| ptr -= index; |
| index = 0; |
| } |
| |
| const char *findPtr = reinterpret_cast<const char *>(memchr(ptr, c, |
| nextBlockIndex - index)); |
| if (findPtr) |
| return qint64(findPtr - ptr) + index + pos; |
| |
| if (nextBlockIndex == maxLength) |
| return -1; |
| } |
| index = nextBlockIndex; |
| } |
| return -1; |
| } |
| |
| qint64 QRingBuffer::read(char *data, qint64 maxLength) |
| { |
| const qint64 bytesToRead = qMin(size(), maxLength); |
| qint64 readSoFar = 0; |
| while (readSoFar < bytesToRead) { |
| const qint64 bytesToReadFromThisBlock = qMin(bytesToRead - readSoFar, |
| nextDataBlockSize()); |
| if (data) |
| memcpy(data + readSoFar, readPointer(), bytesToReadFromThisBlock); |
| readSoFar += bytesToReadFromThisBlock; |
| free(bytesToReadFromThisBlock); |
| } |
| return readSoFar; |
| } |
| |
| /*! |
| \internal |
| |
| Read an unspecified amount (will read the first buffer) |
| */ |
| QByteArray QRingBuffer::read() |
| { |
| if (bufferSize == 0) |
| return QByteArray(); |
| |
| bufferSize -= buffers.constFirst().size(); |
| return buffers.takeFirst().toByteArray(); |
| } |
| |
| /*! |
| \internal |
| |
| Peek the bytes from a specified position |
| */ |
| qint64 QRingBuffer::peek(char *data, qint64 maxLength, qint64 pos) const |
| { |
| Q_ASSERT(maxLength >= 0 && pos >= 0); |
| |
| qint64 readSoFar = 0; |
| for (const QRingChunk &chunk : buffers) { |
| if (readSoFar == maxLength) |
| break; |
| |
| qint64 blockLength = chunk.size(); |
| if (pos < blockLength) { |
| blockLength = qMin(blockLength - pos, maxLength - readSoFar); |
| memcpy(data + readSoFar, chunk.data() + pos, blockLength); |
| readSoFar += blockLength; |
| pos = 0; |
| } else { |
| pos -= blockLength; |
| } |
| } |
| |
| return readSoFar; |
| } |
| |
| /*! |
| \internal |
| |
| Append bytes from data to the end |
| */ |
| void QRingBuffer::append(const char *data, qint64 size) |
| { |
| Q_ASSERT(size >= 0); |
| |
| if (size == 0) |
| return; |
| |
| char *writePointer = reserve(size); |
| if (size == 1) |
| *writePointer = *data; |
| else |
| ::memcpy(writePointer, data, size); |
| } |
| |
| /*! |
| \internal |
| |
| Append a new buffer to the end |
| */ |
| void QRingBuffer::append(const QByteArray &qba) |
| { |
| if (bufferSize != 0 || buffers.isEmpty()) |
| buffers.append(QRingChunk(qba)); |
| else |
| buffers.last().assign(qba); |
| bufferSize += qba.size(); |
| } |
| |
| qint64 QRingBuffer::readLine(char *data, qint64 maxLength) |
| { |
| Q_ASSERT(data != nullptr && maxLength > 1); |
| |
| --maxLength; |
| qint64 i = indexOf('\n', maxLength); |
| i = read(data, i >= 0 ? (i + 1) : maxLength); |
| |
| // Terminate it. |
| data[i] = '\0'; |
| return i; |
| } |
| |
| QT_END_NAMESPACE |